Heretofore, as a technique in this field, there is a fluid control valve 100 disclosed in Patent Document 1 indicated below.
As shown in FIG. 10, the fluid control valve 100 is configured in a manner that a resin valve upper body 102 is connected to an upper surface of a resin valve body 101 and a diaphragm valve element 103 is held between the resin valve body 101 and the resin valve upper body 102. The fluid control valve 100 is arranged in a manner to slide a piston 105 in a downward direction when air is supplied into the upper body 102 through an operation port 104, so that the diaphragm valve element 103 is brought into contact with a valve seat 106. When the air is not supplied to the operation port 104, the piston 105 is urged by a restoring spring 107 to slide in an upward direction, thereby separating the diaphragm valve element 103 from the valve seat 106. While the diaphragm valve element 103 is separated from the valve seat 106, fluid flowing in a first passage 108 is allowed to flow through a valve chamber 109 and then into a second passage 110.
Fluid control valves disclosed in other patent documents have the similar configurations and operational effects to the above.